Suja, Krishnan; Dr.Prathapachandra Kurup,M R(Cochin University of Science and Technology, June , 2008)

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Abstract:

Coordination chemistry of pentadentate 2,6-diacetylpyridine
bis(thiosemicarbazone) Schiff base ligands has been intensively studied due to the versatility of the molecular chain in order to obtain very different
geometries as well as their broad therapeutic activity. Metal complexes of
thiosemicarbazone with aldehydes and ketones have been widely reported.
But there have been fewer reports on potential pentadentate
bis(thiosemicarbazones) formed from 2,6-diacetylpyridine. Keeping these in
view, we have synthesized four bis(thiosemicarbazone) systems with
2,6-diacetylpyridine. In the present work, the chelating behavior of
bis(thiosemicarbazones) are studied, with the aim of investigating the
influence of coordination exerts on their conformation and or configuration, in
connection with the nature of the metal and of the counter ion. The selection
of the 2,6-diacetylpyridine as the ketonic part was based on its capability to
form polynuclear complexes with different coordination number. The doubled
armed bis(thiosemicarbazones) can coordinate to a metal centre as dianionic
ligand by losing its amide protons or it can coordinate as monoanionic ligand
by losing its amide proton from one of the thiosemicarbazone moiety or it can
also be coordinate as neutral ligand. Hence it is interesting to explore the
coordinating capabilities of these ligands whether in neutral form or anionic
form and to study the structural variations occurring in the ligands during
complexation such as change in conformation.

Description:

Department of Applied Chemistry,
Cochin university of Science and Technology